One of the most iconic sights in London is about to change its shape-it will still be recognizable for what it is, but will be more refined, better equipped and more efficient that its predecessors. London's black cab, or the "Hackney Carriage," has been an intrinsic part of the capital city's scenery since the advent of the car. However, they have not always projected the best image, environmentally speaking, because in the days before we cared or were concerned, they had a tendency to belch clouds of smoke and rattle your teeth when idling at traffic lights. Over the years, though, they have gently improved with the generation before this new one being a country mile better than anything that had gone before it. However, although only launched in 2002, the TXII was already beginning to show signs of age in the clean city environment that is nowadays so high on the political agenda, leading to its manufacturers, LTI (London Taxis International) Vehicles, the UK's largest indigenous vehicle manufacturer, to develop a new model.

According to the Public Carriage Office (PCO), the public body that has always had the responsibility for licensing cabs in London, the city's taxi fleet is estimated to be responsible for 12% of the oxides of nitrogen (NOx) and 24% of the particulate matter (PM10) from road transport emissions in central London. NOx and PM10 are the key local air pollutants. As of July 1, 2007 all taxis that are of a Euro 2 emissions standard will, when presented for their annual licensing inspection, be required to have either PCO/EST (Energy Saving Trust) approved emissions reduction equipment fitted or an approved conversion to run on alternative fuels as a requirement of licensing. The screw tightens further when no taxi will be licensed after June 30, 2008 unless it meets Euro 3 emission levels or better.

It is not unusual for a black cab to cover more than 1,000,000 miles in a 10 year period so in addition to the need for them to be distinctive and easily recognizable, they have to be durable, reliable and fit for purpose, so the choice of engine by the manufacturers is not lightly made. The latest cab from LTI, the TX4-a reference to the FX4 that was launched in 1959-is powered by a Euro IV compliant twin overhead cam, common rail 2.5-liter turbo-diesel engine with twin balancer shafts. The engine is supplied by Italian VM Motori. The engine mapping has been configured to supply maximum torque at low speeds for quick acceleration and improved flexibility across a wide power band for optimum performance in traffic and on the open road, all with the lowest possible emissions and fuel consumption. The engine can also use 5% bio-diesel mix without modification. "Some people will want to know why we have moved away from using a Ford-sourced diesel engine as we did with the TXII taxi," said Matthew Cheyne, sales and marketing director for LTI Vehicles. "There are several reasons. Seventy percent of our customers specify an automatic transmission, and the new VM engine comes complete with such a unit which is specifically compatible for use with its latest Euro IV engine. VM produce engines for markets and manufacturers around the world, and since our taxis are now sold to world markets we needed to change to a world engine. Another reason is the fact that a Ford unit was not suitable for fitment to our new TX4 left-hand drive models, so again this meant a change of engine supplier."

Other new features include the transmissions-a Chrysler five-speed auto box and an Eaton five-speed manual, anti-lock braking-a first for London cabs-and new all-round coil suspension system with anti-roll control for a smooth and more comfortable ride. The rear of the vehicle has also been updated with new light clusters, a high rear brake light and improved parcel shelf and plinth. At the front are a totally new hood and a stylish new mesh radiator grille. Naturally, it still has the famous 25 feet turning circle required by the PCO.

Being a vehicle that is specifically designed to take passengers on short rides, the manufacturers have put great thought into the interior. While it may not be the luxury boudoir of a Jaguar, it is far from being functional-it is lighter, brighter and more comfortable. It is also spacious enough to accommodate wheelchair users easily. There is an integral fold-down ramp with extension which is easy to use and designed with a shallow angle for ease of access and departure. Once in place, the wheelchair and passenger are secured using special harnesses and extendable seat belts. There is also a swivel seat to assist people with reduced mobility. Other features include an adjustable centre rear seat belt harness to suit younger and smaller passengers from 18 kg upward, 3-point seat belts are fitted to all seats and individual head restraints for every passenger. There is a swing door mechanism for ease of use, greater visibility for traffic upon entry/exit and safer for hands and fingers.

As on average taxi drivers spend more than 3,000 hours a year in their cabs, the manufacturers have introduced features to make their lives just that bit more comfortable including an ergonomic seat with lumbar support and armrest. With the command driving position and large glass area all around the vehicle, including a one-piece rear window, the TX4 provides visibility so operators can see any potential hazards or fares with ease. To protect the driver from external attacks, the vehicle has a tough Plexiglas Resist 65 high-resistant screen between the driver's compartment and the passenger cabin.

"We have invested three years of development and nearly $10-million in bringing the TX4 to market," said Peter Shillcock, managing director of LTI Vehicles. "We are committed to continually improving our taxis and the development of the TX4 has undergone more component and road testing than anything we have ever built. Over one million kilometers of testing, equivalent to 30 times around the world, has taken place. This includes 5,000 kilometers of chassis and suspension durability testing over Pave cobbled road surfaces. The TX4 has been tested in real-life extreme hot and cold climates and simulated conditions using the wind tunnel at MIRA-the Motor Industry Research Association in central England. We believe without question that the TX4 is quite simply the best purpose-built taxi ever made and it will set the standard for years to come. The TX4 is without doubt a milestone not only for LTI Vehicles but the whole taxi industry."

Although LTI, which can trace its roots back to 1919 through Carbodies, which over time eventually transmuted into LTI, it was not until 1948 that the company built its first taxi, the FX3, based on an Austin vehicle. Since that time more than 100,000 taxis have been built. Its current output is just under 3,000 units a year, all produced at its Coventry manufacturing facility in the UK. Making a break with history, the vehicle will also be produced abroad for the first time. Late last year, Manganese Bronze Holdings, the parent company of LTI Vehicles, announced it had signed an agreement with Chinese car manufacturer Zhejiang Geely to establish a $100-million joint venture company to produce the taxi in Shanghai for the Chinese market. From mid-2008 the joint company will produce 20,000 London taxis for sale in China, and there is the possibility of supplying some Chinese sourced components to LTI's UK manufacturing headquarters in Coventry. So what has long been a familiar sight in London looks set to make its special mark in other parts of the world.

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